Spin-signal enhancement in a lateral spin valve reader

ABSTRACT

A lateral spin valve reader that includes a detector structure located proximate to a bearing surface and a spin injection structure located away from the bearing surface. The lateral spin valve reader also includes a channel layer extending from the detector structure to the spin injection structure. An exterior cladding, disposed around the channel layer, suppresses spin-scattering at surfaces of the channel layer.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation application of U.S. application Ser.No. 14/718,406 filed on May 21, 2015, the content of which isincorporated by reference in its entirety.

BACKGROUND

Data storage devices commonly have a recording head that includes a readtransducer that reads information from a data storage medium and a writetransducer that writes information to a data storage medium.

In magnetic data storage devices such as disc drives, a magnetoresistive(MR) sensor such as a Giant Magnetoresistive (GMR) sensor or a TunnelJunction Magnetoresistive (TMR) sensor has traditionally been employedas the read transducer to read a magnetic signal from the magneticmedia. The MR sensor has an electrical resistance that changes inresponse to an external magnetic field. This change in electricalresistance can be detected by processing circuitry in order to readmagnetic data from the adjacent magnetic media.

The ever increasing need for increased data storage necessitates everincreasing data density in magnetic data storage devices. One way toincrease data density is to decrease the size and spacing of magneticbits recorded on the media. The read sensor is generally sandwichedbetween a pair of magnetic shields, the spacing between which determinesthe bit length, also referred to as gap thickness. Sensors such as GMRor TMR sensors are constructed as a stack of layers all formed upon oneanother sandwiched between the magnetic shields. Accordingly, theability to reduce the spacing between shields with such a sensorstructure is limited.

SUMMARY

The present disclosure relates to a lateral spin valve reader thataddresses scaling challenges posed by greater data density requirementsand includes one or more features that help suppress spin-scatteringfrom the reader. The lateral spin valve reader includes a detectorstructure located proximate to a bearing surface and a spin injectionstructure located away from the bearing surface. The lateral spin valvereader also includes a channel layer extending from the detectorstructure to the spin injection structure. An exterior cladding,disposed around the channel layer, suppresses spin-scattering atsurfaces of the channel layer.

Other features and benefits that characterize embodiments of thedisclosure will be apparent upon reading the following detaileddescription and review of the associated drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a data storage system.

FIG. 2 is a generalized functional block diagram of a data storagesystem.

FIG. 3A is a schematic diagram of a cross-section of one embodiment of arecording head that reads from and writes to a storage medium.

FIG. 3B is a schematic diagram of a cross-section of another embodimentof a recording head that reads from and writes to a storage medium.

FIG. 3C is a schematic diagram of a cross-section of yet anotherembodiment of a recording head that reads from and writes to a storagemedium.

FIGS. 4A, 4B and 4C show corresponding plots of scattering potential ina channel in differing dielectric environments.

FIG. 5 is a schematic perspective view of a lateral spin valve reader inaccordance with one embodiment.

FIGS. 6A, 6B and 6C are schematic diagrams of cross-sections of lateralspin valve readers with different lead terminal configurations.

FIGS. 7A, 7B and 7C are diagrammatic illustrations showing differentviews of a lateral spin valve reader in accordance with one embodiment.

FIG. 8 is a diagrammatic illustration of a cross-section of amulti-sensor reader in accordance with one embodiment.

FIG. 9 is a simplified flow diagram of a method embodiment.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

Magnetic reader embodiments described below relate to lateral spin valve(LSV) readers that include a spin injector, a detector and a channellayer extending from the spin injector to the detector. The spininjector injects electron spins into the channel layer, which transportsthe spins to the detector. At the detector, the spins aid in detectingbits stored on a magnetic data storage medium. To suppressspin-scattering at surfaces of the channel layer, different embodimentsemploy an exterior cladding that is disposed around the channel layer.Prior to providing additional details regarding the differentembodiments, a description of an illustrative operating environment isprovided below.

FIGS. 1 and 2 together show an illustrative operating environment inwhich certain specific embodiments disclosed herein may be incorporated.The operating environment shown in FIGS. 1 and 2 is for illustrationpurposes only. Embodiments of the present disclosure are not limited toany particular operating environment such as the operating environmentshown in FIGS. 1 and 2. Embodiments of the present disclosure areillustratively practiced within any number of different types ofoperating environments.

FIG. 1 is a perspective view of a hard disc drive 100. Hard disc drivesare a common type of data storage system. While embodiments of thisdisclosure are described in terms of disc drives, other types of datastorage systems should be considered within the scope of the presentdisclosure. The same reference numerals are used in different figuresfor same or similar elements.

Disc drive 100 includes a data storage medium (for example, a magneticdisc) 110. Those skilled in the art will recognize that disc drive 100can contain a single disc or multiple discs. Medium 110 is mounted on aspindle motor assembly 115 that facilitates rotation of the medium abouta central axis. An illustrative direction of rotation is shown by arrow117. Each disc surface has an associated recording head 120 that carriesa read transducer and a write transducer for communication with thesurface of the disc. Each head 120 is supported by a head gimbalassembly 125. Each head gimbal assembly (HGA) 125 illustrativelyincludes a suspension and a HGA circuit. Each HGA circuit provideselectrical pathways between a recording head and associated hard discdrive electrical components including preamplifiers, controllers,printed circuit boards, or other components. Each suspensionmechanically supports an HGA circuit and a recording head 120, andtransfers motion from actuator arm 130 to recording head 120. Eachactuator arm 130 is rotated about a shaft by a voice coil motor assembly140. As voice coil motor assembly 140 rotates actuator arm 130, head 120moves in an arc between a disc inner diameter 145 and a disc outerdiameter 150 and may be positioned over a desired track such as 152 toread and/or write data.

FIG. 2 is a generalized block diagram of illustrative control circuitryfor the device shown in FIG. 1. The control circuitry includes aprocessor or controller 202 that directs or manages the high leveloperations of device 100. An interface circuit 204 facilitatescommunication between device 100 and a host device 250. A read/writechannel 206 operates in conjunction with a preamplifier/driver circuit(preamp) 208 to write data to and to read data from a data storagemedium such as medium 110 in FIG. 1. Preamp 208 also optionally acts asa power supply to electrical components included in a recording headsuch as a read transducer, a write transducer, heaters, etc. Preamp 208is illustratively electrically connected to recording head 120 through aHGA circuit that is connected to preamp 208 and to one or more recordinghead 120 electrical connection points. A servo circuit 210 providesclosed loop positional control for voice coil motor 140 that positionsrecording head 120.

FIG. 3A is a schematic diagram showing a cross-sectional view ofportions of a recording head 300 and a data storage medium 350 takenalong a plane substantially normal to a plane of a bearing surface (forexample, an air bearing surface (ABS)) 302 of recording head 300. Therecording head elements shown in FIG. 3A are illustratively included ina recording head such as recording head 120 in FIGS. 1 and 2. Medium 350is illustratively a data storage medium such as medium 110 in FIG. 1.Those skilled in the art will recognize that recording heads andrecording media commonly include other components. Embodiments of thepresent disclosure are not limited to any particular recording heads ormedia. Embodiments of the present disclosure may be practiced indifferent types of recording heads and media.

Recording head 300 includes a write pole 305, a magnetization coil 310,a return pole 315, a top shield 318, a read transducer 320, a bottomshield 322 and a wafer overcoat 336. Storage medium 350 includes arecording layer 355 and an underlayer 360. Storage medium 350 rotates inthe direction shown by arrow 365. Arrow 365 is illustratively adirection of rotation such as arrow 117 in FIG. 1.

In an embodiment, electric current is passed through coil 310 togenerate a magnetic field. The magnetic field passes from write pole305, through recording layer 355, into underlayer 360, and across toreturn pole 315. The magnetic field illustratively records amagnetization pattern 370 in recording layer 355. Read transducer 320senses or detects magnetization patterns in recording layer 355, and isused in retrieving information previously recorded to layer 355.

In the embodiment shown in FIG. 3A, read transducer 320 is a LSV reader.LSV reader 320 includes a spin injector 324, a detector 326 and achannel layer 328 that extends from spin injector 324 to detector 326.

The spin injector 324 may include an electrically conductive, magneticlayer (not separately shown) that has a magnetization that is pinned ina direction (preferably perpendicular to the bearing surface). Pinningof the magnetization of the pinned magnetic layer may be achieved by,for example, exchange coupling with a layer of anti-ferromagneticmaterial (not separately shown).

The detector 326 may include a magnetic, electrically conductive layerhaving a magnetization that is free to move in response to a magneticfield, and can therefore be referred to herein as a free layer (FL).Injector 324 and/or detector 326 may be separated from channel layer 328by a thin electrically insulating barrier layer 338. A thickness ofbarrier layer 328 is denoted by reference numeral 340.

The portion of LSV reader 320 proximate to the bearing surface 302 doesnot include relatively thick synthetic antiferromagnetic (SAF) andantiferromagnetic (AFM) stacks that are typically present in, forexample, current perpendicular-to-plane (CPP) Tunnel JunctionMagnetoresistive (TMR) readers. Therefore, a spacing between top shield318 and bottom shield 322 of LSV reader 320, which is denoted by s, issubstantially less than a shield-to shield spacing in, for example, aCPP TMR reader. It should be noted that, in the interest ofsimplification, shield-to-shield spacing s in the Z-axis direction inFIG. 3A is shown as being uniform along a length (in the Y-axisdirection) of LSV reader 320. However, in different embodiments, toaccommodate a multi-layered injector 324, a shield-to-shied spacing awayfrom the bearing surface 302 may be substantially greater than theshield-shield spacing s proximate to the bearing surface 302.

For allowing a detection current to flow to detector 326, spin injector324 is connected to a current source (not shown) via terminal 330.Detector 326 is connected to a suitable voltage measuring device (notshown) via terminal 332.

First, the detection current from the current source is made to flowthrough the spin injector 324 and through the channel layer 328. Thisflow of current causes electron spins to accumulate in channel layer328, which then transports the spins to the detector 326.

When the spins are transported to the detector 326, an electricpotential difference, which varies depending upon an external magneticfield, appears between the detector 326 and the channel layer 328. Thevoltage measuring device detects electric potential difference appearingbetween the detector 326 and the channel layer 328. In this manner, theLSV reader 320 can be applied as an external magnetic field sensor fordetecting bits stored on a magnetic data storage medium such as 350.

As noted above, to suppress spin-scattering at surfaces of the channellayer, different embodiments employ an exterior cladding (such as 334)that is disposed around the channel layer 328. A thickness of claddinglayer 334 is denoted by reference numeral 342. FIG. 3B shows anotherembodiment of a recording head denoted by reference numeral 360. Otherthan injector 324 and detector 326 being on a same side of channel layer328 in recording head 360 and bottom shield 322 being separated into twoelectrically-isolated portions, recording head 360 is substantiallysimilar to recording head 300. FIG. 3C shows yet another embodiment of arecording head denoted by reference numeral 362. Recording head 362 issubstantially similar to recording head 360 (of FIG. 3B), but includesinjector 324 and detector 326 above channel layer 328 instead of belowthe channel layer 328 as in recording head 360 (of FIG. 3B). Likerecording head 300, recording heads 360 and 362 employ an exteriorcladding 334 to suppress spin-scattering at surfaces of the channellayer 328. It should be noted that cladding 334 is included as aseparate element that is present in addition to wafer overcoat 336.Details regarding spin-scattering and how spin scattering is addressedare provided below.

As indicated above, a LSV reader inherently relies on the traversal of aspin-coherent (polarized) current from an injector lead into and acrossa non-magnetic channel layer and finally measured at a detector lead.The traversal of spin current across the channel medium encountersvarious scattering centers that scatter electron momentum. Thescattering randomizes the electron spins (also termed de-coherence orspin-flipping). The effect of the randomization of electron spin in theLSV channel is fewer spin-coherent electrons that make it to thedetector contact, which ultimately results in a diminished signal levelat the detector lead. Therefore, the minimization of spin-scattering inthe LSV channel is essential to help maximize the reader signal levelregardless of the LSV topology. Some of these scatteringcenters/mechanisms are extrinsic (impurity, roughness and surfaces) andmay be suppressed by using suitable device engineering techniques.Others are material dependent (phonon, alloy, dislocation) and setintrinsic limits to a spin mean free path (l_(s)=√{square root over(Dτ_(s))}) where D is a diffusion constant and τ_(s) is a spinrelaxation time. One example is the presence of an impurity within orsurrounding the spin-channel that scatters spin by coulomb interaction.The scattering potential, V_(coul), is given by:

$\begin{matrix}{{V_{coul}\left( {\rho,z} \right)} = {\sum\limits_{n = {- \infty}}^{\infty}\frac{{qy}^{n}}{4{\pi ɛ}_{s}\varepsilon_{o}\sqrt{\rho^{2} + {{z - z_{n}}}^{2}}}}} & {{Equation}\mspace{14mu} 1}\end{matrix}$where q is the elemental charge constant, γ=(∈_(s)−∈_(e))/(∈_(s)+∈_(e)),where ∈_(s) is a permittivity of the channel and ∈_(e) is a permittivityof an environment of the channel, gives a measure of dielectric mismatchbetween the channel and the dielectric environment, ∈_(s) is apermittivity of free space measured in farads per meter (F/m) orA²·s⁴·kg⁻¹·m⁻³ (where A is current in amperes, s is time in seconds, kgis mass in kilograms and m is length in meters), ρ is the in-plane spacevector in the channel, and z is the direction of channel thickness withz_(n)=nd where d is channel width and n=±1, ±2 . . . . A purpose foroutlining the coulomb scattering potential is to show that it isinversely proportional to a relative dielectric constant (∈_(s) or∈_(e)) which is variable with the dielectric environment of thespin-channel. A discussion within the context of the LSV is given below.The technique described below provides a solution to suppress at leastsome of the extrinsic spin scattering in order to maximize the detectedsignal of a LSV-based magnetic reader.

The LSV reader signal is dependent on the diffusion of electronpolarized electron spins and therefore the spin diffusion length, λ_(s)is the central quantity of interest and is defined as,λ_(s)=√{square root over (Dτ _(s))}  Equation 2where D is the diffusion length in the conduction medium (LSV channel)and τ_(s) is the spin scattering length and is related to the momentumrelaxation time in metals and semiconductors by:τ_(s)=ατ_(m)  Equation 3where τ_(m) is the momentum relaxation time and α is a weightingconstant that relates momentum and spin scattering times to propertiesof a band structure (spin orbit coupling parameter) of the material. Themomentum relaxation time is also a critical component in setting theconductivity of a material, which is given by the Drude relationship,

$\begin{matrix}{\sigma = \frac{{qN\tau}_{m}}{m^{*}}} & {{Equation}\mspace{14mu} 4}\end{matrix}$where N is the charge density, and m* is the effective mass of theelectron moving through the periodic crystal lattice. The (total)momentum relaxation time may be related to individual relaxation timesvia Matthiessen's rule,

$\begin{matrix}{\frac{1}{\tau_{m}} = {\sum\limits_{i}\frac{1}{\tau_{i}}}} & {{Equation}\mspace{14mu} 5}\end{matrix}$such that individual scattering mechanisms may be considered separatelyand incorporated into the conglomerate (i.e., total) momentum relaxationtime and therefore the spin-relaxation time. This methodology gives asubstantially accurate approximation for the calculation of theindividual spin-relaxation times and their total contribution to thespin diffusion length that determines the LSV detection signal.

One technique to reduce spin scattering is to fully clad the LSV channelwith a high dielectric constant, non-magnetic, non-conductive materialfor spin-scattering suppression which leads to higher spin-conductivity(drift and/or diffusion) and thus, a higher reader signal for scaled(thin) channels. For low-dimensional (single nanometers-10 nanometers)systems, electron transport is enhanced by cladding the conductionchannel by a judiciously chosen dielectric material. That is, bysurrounding the conduction channel of an electronic device with adielectric cladding, surface or remote ionized charge that may interactwith the conduction electrons by coulomb interaction may be suppressedvia the modification of the electric field through the dielectricenvironment. The suppression is due to the boundary condition at theinterface of the channel and dielectric that causes a discontinuity inthe fields that depend on the dielectric mismatch.

For illustration purposes of the screening effect, the scatteringpotential in Equation 1 may be considered for a charged point defectcentered in the channel. FIGS. 4A, 4B and 4C show corresponding plots ofcoulomb potentials in a channel and how the channel is manipulated by adielectric environment. The channel thickness is in the z-direction andthe in-plane dimensions are in the x- and y-directions (indicated by ρin FIG. 4B). The channel is of sufficiently small width (≦10 nm) so thatthe dielectric material imposes a hard-wall confining potential suchthat the spin-polarized conduction electrons within the channel are(quantum) confined to only the channel region. Under these conditions,the momentum scattering time, and therefore conductivity, may be derivedby perturbation methods as indicated in equations included above. Asshown in FIG. 4A, a dielectric permittivity less than that of thechannel causes spreading or leakage of the potential contour of thescattering potential, giving it a longer range interaction within andout of the channel. If the dielectric constant of the channel is matchedto its environment, as in FIG. 4B, the potential spreading is as if noconfinement in the channel exists. In FIG. 4B, the channel thickness isd (i.e., −d/2 to d/2). For the case where the environment bestows ahigher dielectric constant than the channel material, the coulombinteraction is suppressed by the environment and therefore thescattering potential inside the channel is damped (FIG. 4C). Takingadvantage of this fact for the LSV reader, cladding the reader with ahigh dielectric constant material allows for diminished coulombscattering within the conduction channel and therefore spin scatteringis also suppressed.

A dielectric environment plays a critical role in setting carriermobility in low-dimensional semiconductor channels. For extremely scaled(thin) two-dimensional carbon channels, surface phonon coupling at theconduction channel/dielectric interface may also play a strong role indetermining the variety of dielectric. Since the LSV channel serves asthe primary scaling element, it is suitable to employ such materials aslow-dimensional semiconductors, two-dimensional carbon crystallinefilms, and the transition-metal dichalcogenides as these systems are allsubstantially ideally suited for geometric scaling and long spin meanfree paths.

FIG. 5 is a schematic perspective view of LSV reader 320 of FIG. 3A. Asnoted earlier, LSV read 320 includes injector 324, detector 326, channellayer 328 and cladding 334. As can be seen in FIG. 5, substantially allsurfaces of channel layer 328, other than the bearing surface portionand surface portions that interface with injector 324 and detector 326,are encapsulated with cladding 334, which may comprise a suitable typeof dielectric material described further below. In some embodiments,only top and bottom surfaces of channel layer 328 may be covered bycladding 334. It should be noted that the Z-axis direction isperpendicular to the top and bottom surfaces of channel layer 328. Thedielectric material can be atomic layer deposited, chemical vapordeposited, or any solid/crystal material deposition method may also beutilized. It is desirable that the deposition method yield conformaldielectric coverage in terms of convenience for side-wall coverage butmay depend on the overall process. Similar dielectric cladding 334 maybe provided for readers 320 in FIGS. 3B and 3C.

The LSV reader is electrically isolated from any surrounding conductorthat may short injector and detector leads (not shown in FIG. 5). Suchsurrounding conductors may include magnetic shields and/or secondaryspin injectors. It is further noted that two, three, four, or any othernumber of contacts may be implemented in various embodiments of the LSVreader. The contact configuration utilized depends on a type ofdetection scheme and application. FIG. 6A shows an example of an LSVreader such as 320 that has a two-terminal/two-contact (602 and 604)configuration. FIG. 6B shows an example of an LSV reader 320 that has athree-terminal/three-contact (602, 604 and 606) configuration, and FIG.6C shows an example a four-terminal/four-contact (602, 604, 606 and 608)configuration.

The choice of dielectric material species is important for thedielectric cladding. Two distinct and simultaneous requirements on thedielectric are made, 1) that the cladding material be of a wide-band gapvariety (E_(g) (energy gap) >3 eV (electron volts), for example) with asufficient energy offset (i.e. work function) to the metal channel, and2) that the dielectric constant, ∈_(r), be high (>2∈_(o)). Therefore, apartial list of material classes as well as dielectrics that meet theserequirements is given in Table 1 below. Dielectric cladding may beachieved by utilization of wide bandgap semiconductors (polar andnon-polar) as well as insulators (e.g. oxides and nitrides) as twodistinct classes of materials. Within the framework of those classes,some examples of material species are given in Table 1 below.

TABLE 1 Insulators Select Semiconductors (high dielectric constant (k))Species E_(g)(eV)/ε_(r) Species E_(g)(eV)/ε_(r) AlN (Aluminum Nitride) + 6.2/9 Al₂O₃ (Sapphire/Aluminum  8.8/11 alloys Oxide) GaN (GalliumNitride) + alloys  3.4/8.9 HfO₂ (Hafnium(IV) Oxide)  6.0/15 GaAs(Gallium Arsenide) + 1.42/11 TiO₂ (Titanium Dioxide)  3.2/25 alloys ZnO(Zinc Oxide) + alloys 3.37/~8 ZrO₂ (Zirconium Dioxide)  5.8/10-50Diamond  5.5/<10 Si₃N₄ (Silicon Nitride)  5.3/7 Ta₂O₅ (Tantalum Oxide) 4.4/20 Titanates (BaTiO₃ (Barium 3.7+/100-1000s Titanate), SrTiO₃(Strontium Titanate), etc.)

The cladding layer thickness (denoted by reference numeral 342 in FIGS.3A and 3B) is not limited to the same thickness as the tunnel barrier.On the contrary, it should be of sufficient thickness that the channelmobile electron wave function's evanescent tail that penetrates into thecladding layer vanishes. This requirement depends on the work functionbetween the dielectric and the channel metal. In certain embodiments, athickness of the exterior cladding may be greater than 3 nanometers (nm)in thickness. In other embodiments, the cladding layer thickness may beslightly less (for example, 2.5-2.9 nm). An upper limit for thethickness the cladding may be about 20 nanometers. However, in differentembodiments, cladding of any suitable thickness may be employed. Typicaltunnel barrier thicknesses (denoted by reference numeral 340 in FIGS. 3Aand 3B) are no more than 1 nm thick. However, in certain embodiments,tunnel barriers having greater thicknesses (for example, 1.5 nm) may beused. A lower limit for tunnel barrier thickness may be about 5angstroms. Furthermore, the dielectric species of the cladding layerneed not be similar to the tunnel barrier material species. This is dueto the differing requirements for the respective dielectrics. Thedielectric used for LSV channel cladding must confine the electron wavefunction into the channel region with little “leakage” into thedielectric. Additionally, the dielectric constant should be high suchthat the electric field of impurity defects is contained in the channel.There may not be similar requirements for the barrier layer. Forexample, if the tunnel barrier is composed of MgO, then the dielectriccladding layer may be Al₂O3, AlN, Si₃N₄, or any species given in thelist above in Table 1. In some embodiments, the cladding may comprisemultiple layers, with each layer formed of a different material.

As indicated earlier, the bias configuration for a LSV reader mayinclude 2, 3, or 4 terminals for a single reader. However, in someembodiments, it may be more practical from an implementation standpointthat the reader is either 2-terminal as illustrated in FIG. 6A or3-terminal as illustrated in FIG. 6B.

FIGS. 7A, 7B and 7C are cross-sectional, top and bearing surface views,respectively of LSV reader 320 in accordance with one embodiment. Topshield 318 and bottom shield 322, which are not shown in FIG. 5, areshown in FIGS. 7A and 7C. The top view shown in FIG. 7B in with shield318 excluded. In the embodiment of LSV reader 320 shown in FIGS. 7A, 7Band 7C, cladding 334 may comprise multiple layers, with each of themultiple layers being formed of a different dielectric material. Dashedlines denoted by reference numeral 700 indicate optional multiplelayers.

As indicated earlier in connection with the description of FIGS. 3A and3B, an LSV reader such as 320 has a substantially narrowshield-to-shield spacing proximate to a bearing surface such as 302. Theshield-to-shield spacing in the reader such as 320 is determinedsubstantially by the channel and free layers (FL). Therefore, it is asuitable reader design to implement in a multi-sensor configurationwhere two or more readers are stacked on top of each other within asingle recording head such as 300. An example of a dual-readerconfiguration is shown in FIG. 8. The embodiment of reader 800 in FIG. 8includes a top shield 318 a bottom shield 322 and LSV readers 320A and320B interposed between top shield 318 and bottom shield 322. Reader320A includes an injector 324A, a detector 326A, a channel 328A and acladding 334A. Similarly, reader 320B includes an injector 324B, adetector 326B, a channel 328B and a cladding 334B. In the embodimentshown in FIG. 8, a two-terminal connection configuration is used foreach shield. Accordingly, bottom shield 322 and a middle shield 802 areutilized for electrical connection to reader 320A. Similarly, a middleshield 804 and top shield 318 are utilized for electrical connection toreader 320B. A suitable isolation layer 806 is interposed between middleshields 802 and 804 to provide the necessary electrical isolationbetween the shields. It should be noted that FIG. 8 is an illustrativeembodiment of a multi-sensor reader and, in other embodiments, more thantwo sensors may be employed.

In the multi-sensor configuration, a critical parameter is the FL-to-FLspacing, d (in FIG. 8), and is conventionally set by the additivethicknesses of the stack SAF, mid-shields, and isolation layers.Reducing d enables the multi-sensor reader to be implemented in a higherlinear density drive. Substantially drastic d-spacing reduction may beachieved by implementing LSV-based magnetic readers because, as notedabove, they eliminate the thicknesses of SAF and AFM stacks at thebearing surface that are typically present in, for example, CPP TMRreaders.

FIG. 9 shows a simplified flow diagram 900 of a method forming arecording head in accordance with one embodiment. At step 902, asuitable substrate is provided. At step 904, a bottom shield is formedover the substrate. This is followed by step 906 at which an injectorstructure and a first portion of a cladding are formed over the bottomshield. At step 908, a channel layer over the injector structure andover the first portion of the cladding. At step 910, a second portion ofthe cladding is formed on sides of the channel layer. At step 912, adetector structure and a third portion of the cladding are formed overthe channel layer such that the first portion of the cladding, thesecond portion of the cladding and the third portion of the claddingsurround the channel layer.

Although various uses of the LSV reader with the cladding to suppressspin-scattering are disclosed in the application, embodiments are notlimited to the particular applications or uses disclosed in theapplication. It is to be understood that even though numerouscharacteristics and advantages of various embodiments of the disclosurehave been set forth in the foregoing description, together with detailsof the structure and function of various embodiments of the disclosure,this disclosure is illustrative only, and changes may be made in detail,especially in matters of structure and arrangement of parts within theprinciples of the present disclosure to the full extent indicated by thebroad general meaning of the terms in which the appended claims areexpressed. For example, the particular elements may vary depending onthe particular application for the LSV reader with the cladding whilemaintaining substantially the same functionality without departing fromthe scope and spirit of the present disclosure. In addition, althoughthe preferred embodiment described herein is directed to particular typeof LSV reader with the cladding utilized in a particular data storagesystem, it will be appreciated by those skilled in the art that theteachings of the present disclosure can be applied to other data storagedevices without departing from the scope and spirit of the presentdisclosure.

What is claimed is:
 1. A lateral spin valve reader comprising: adetector structure having a surface that forms a portion of a bearingsurface; a first shield in contact with the detector structure; a spininjection structure located away from the bearing surface; a secondshield in contact with the spine injection structure; a channel layerextending from the detector structure to the spin injection structure; atunnel barrier layer between at least one of the detector structure andthe channel layer or the spin injection structure and the channel layer;and an exterior cladding, disposed around the channel layer, configuredto suppress spin-scattering at surfaces of the channel layer, wherein athickness of the exterior cladding relative to the channel layer isbetween about 2.5 nanometers and about 20 nanometers, and wherein athickness of the tunnel barrier layer is less than the thickness of theexterior cladding.
 2. The lateral spin valve reader of claim 1 andwherein the exterior cladding comprises an insulator.
 3. The lateralspin valve reader of claim 2 and wherein the insulator is a highdielectric constant insulator selected from the group consisting ofAl₂O₃, HfO₂, TiO₂, ZrO₂, Si₃N₄, Ta₂O₅, one or more Titanates andcombinations thereof.
 4. The lateral spin valve reader of claim 3 andwherein the one or more Titanates comprise BaTiO₃ and SrTiO₃.
 5. Thelateral spin valve reader of claim 1 and wherein the exterior claddingcomprises a semiconductor.
 6. The lateral spin valve reader of claim 5and wherein the semiconductor is selected from the group consisting ofAlN, alloys comprising AlN, GaN, alloys comprising GaN, GaAs, alloyscomprising GaAs, ZnO, alloys comprising ZnO, Diamond and combinationsthereof.
 7. The lateral spin valve reader of claim 1 and wherein thethickness of the tunnel barrier layer is less than or equal to about 1.5nanometers.
 8. The lateral spin valve reader of claim 1 and wherein thetunnel barrier layer is formed of a first material and the exteriorcladding is formed of a second material that is different from the firstmaterial.
 9. The lateral spin valve reader of claim 1 and wherein thetunnel barrier layer and the exterior cladding are formed of a samematerial.
 10. The lateral spin valve reader of claim 1 and wherein theexterior cladding comprises a bilayer including a first layer comprisinga first dielectric material and a second layer comprising a seconddielectric material that is different from the first dielectricmaterial.
 11. The lateral spin valve reader of claim 5 and wherein theexterior cladding comprises a semiconductor material having an energygap that is greater than or equal to about one electron volt.
 12. Thelateral spin valve reader of claim 2 and wherein the exterior claddingcomprises an insulator material having an energy gap that is greaterthan or equal to about three electron volts.
 13. The lateral spin valvereader of claim 1 and wherein the exterior cladding comprises a materialhaving a dielectric constant that is greater than twice a permittivityof free space.
 14. A lateral spin valve reader comprising: a detectorstructure having a surface that forms a portion of a bearing surface; afirst shield in contact with the detector structure; a spin injectionstructure located away from the bearing surface; a second shield incontact with the spine injection structure; a channel layer extendingfrom the detector structure to the spin injection structure; a tunnelbarrier layer between at least one of the detector structure and thechannel layer or the spin injection structure and the channel layer; andan exterior cladding, disposed around the channel layer, configured tosuppress spin-scattering at surfaces of the channel layer, wherein theexterior cladding comprises a semiconductor, and wherein a thickness ofthe tunnel barrier layer is less than a thickness of the exteriorcladding relative to the channel layer.
 15. The lateral spin valvereader of claim 14 and wherein the semiconductor is selected from thegroup consisting of AlN, alloys comprising AlN, GaN, alloys comprisingGaN, GaAs, alloys comprising GaAs, ZnO, alloys comprising ZnO, Diamondand combinations thereof.
 16. The lateral spin valve reader of claim 14and wherein the exterior cladding comprises a semiconductor materialhaving an energy gap that is greater than or equal to about one electronvolt.
 17. A method of forming a recording head comprising: providing asubstrate; forming a bottom shield over the substrate; forming aninjector structure and a first portion of a cladding over the bottomshield, wherein the injector structure is in contact with the bottomshield; forming a channel layer over the injector structure and over thefirst portion of the cladding; forming a second portion of the claddingon sides of the channel layer; forming a detector structure and a thirdportion of the cladding over the channel layer such that the firstportion of the cladding, the second portion of the cladding and thethird portion of the cladding surround the channel layer, wherein thedetector structure includes a surface that forms a portion of a bearingsurface of the recording head; forming a top shield over the detectorstructure, wherein the top shield is in contact with the detectorstructure; forming a tunnel barrier layer between at least one of thedetector structure and the channel layer or the injector structure andthe channel layer, wherein a thickness of the cladding relative to thechannel layer is between about 2.5 nanometers and about 20 nanometers,and wherein a thickness of the tunnel barrier layer is less than thethickness of the cladding.
 18. The method of claim 17 and wherein thecladding comprises a material having an energy gap that is greater thanthree electron volts.
 19. The method of claim 17 and wherein thecladding comprises a material having a dielectric constant that isgreater than twice a permittivity of free space.